1GMM

Carbohydrate binding module CBM6 from xylanase U Clostridium thermocellum

Summary for 1GMM

• Entry DOI: 10.2210/pdb1gmm/pdb
• Descriptor: CBM6, SULFATE ION, SODIUM ION, ... (5 entities in total)
• Functional Keywords: xylanase, carbohydrate binding module, cbm family 6, xylan binding
• Biological source: CLOSTRIDIUM THERMOCELLUM
• Total number of polymer chains: 1
• Total formula weight: 14274.48

Authors

Czjzek, M.,Mosbah, A.,Bolam, D.,Allouch, J.,Zamboni, V.,Henrissat, B.,Gilbert, H.J. (deposition date: 2001-09-19, release date: 2001-11-28, Last modification date: 2024-05-08)

Primary citation

Czjzek, M.,Bolam, D.,Mosbah, A.,Allouch, J.,Fontes, C.M.,Ferreira, L.M.,Bornet, O.,Zamboni, V.,Darbon, H.,Smith, N.L.,Black, G.W.,Henrissat, B.,Gilbert, H.J.
The Location of the Ligand-Binding Site of Carbohydrate-Binding Modules that Have Evolved from a Common Sequence is not Conserved.
J.Biol.Chem., 276:48580-, 2001

PubMed Abstract: Polysaccharide-degrading enzymes are generally modular proteins that contain non-catalytic carbohydrate-binding modules (CBMs), which potentiate the activity of the catalytic module. CBMs have been grouped into sequence-based families, and three-dimensional structural data are available for half of these families. Clostridium thermocellum xylanase 11A is a modular enzyme that contains a CBM from family 6 (CBM6), for which no structural data are available. We have determined the crystal structure of this module to a resolution of 2.1 A. The protein is a beta-sandwich that contains two potential ligand-binding clefts designated cleft A and B. The CBM interacts primarily with xylan, and NMR spectroscopy coupled with site-directed mutagenesis identified cleft A, containing Trp-92, Tyr-34, and Asn-120, as the ligand-binding site. The overall fold of CBM6 is similar to proteins in CBM families 4 and 22, although surprisingly the ligand-binding site in CBM4 and CBM22 is equivalent to cleft B in CBM6. These structural data define a superfamily of CBMs, comprising CBM4, CBM6, and CBM22, and demonstrate that, although CBMs have evolved from a relatively small number of ancestors, the structural elements involved in ligand recognition have been assembled at different locations on the ancestral scaffold.

PubMed: 11673472
DOI: 10.1074/JBC.M109142200

Experimental method

X-RAY DIFFRACTION (2 Å)